Robert William Pickton is shown in this undated image from a television screen. (Getty Images)

A memoir by Canada’s most infamous serial killer was pulled from the online shelves of Amazon overnight after a petition of more than 50,000 signatures was amassed hours after its release. Robert Pickton is believed to have killed 49 women in gruesome murders on his farm outside of Vancouver before trying to get rid of their bodies by feeding them to the pigs he raised. Many of the women were prostitutes or drug addicts whom he picked up in the city’s red light district. After his arrest, an undercover agent in jail with Pickton recorded him bragging about the murders, saying he wanted to get to 50, and that he had killed more women than prosecutors knew about. He is serving a life sentence for six of the murders.

A poster showing 48 missing women was put on display outside the courthouse during the trial of serial killer Robert Pickton in 2007. (REUTERS/Andy Clark)

In Pickton: In His Own Words, the convicted killer claims he is innocent and was set up by the Royal Canadian Mounted Police. Officials are investigating how he smuggled the book’s manuscript out of prison to have it published.